| T-2 toxin is the strongest toxicity of the A trichothecenes. Due to its strong noxious characteristics, T-2 toxin was used as a chemical and biological weapons in the war. After infected with some fungi under the appropriate conditions, grains are easy to produce mycotoxins. Owing to the increase of botanical ingredients in aquatic feeds, the damage to aquatic animals is increasing, causing quality declining and bringing food safety issues of aquatic products. It is crucial to research the metabolism of T-2 toxin in the aquatic animals. The prior studies about T-2 toxin are mainly concentrated in mammals and birds metabolism in vivo, the researchs on aquatic animals are only a few. It is particularly necessary to make further research on clearance ability and metabolism of T-2toxin in shrimps.The research on the animal metabolism of T-2 toxin is mainly divided into vivo and vitro. The vivo studies mainly focus on the metabolites of T-2 toxin in the tissues, organs and waste of the animals after intake a certain amount of T-2 toxin. As the liver is an important detoxification organs of animals, which contains a lot of detoxification enzymes,the vitro studies mainly use liver microsomal. The vitro metabolism study can provide certain references for further studies in vivo.This dissertation mainly use the shrimp and mice liver microsomal to metabolize T-2toxin in vitro, to find out the metabolic abilities and differences between shrimp and mice.This can be further used for vivo studies of T-2 toxin in shrimp and provide references for its limited standards and risk assessment in aquatic feed.There are four chapters in this thesis. The first chapter introduces the mycotoxin and trichothecenes through the literature reviews, the vivo metabolism of T-2 toxin in different mammals and birds, and the metabolic differences between animals and plants.The second chapter is mainly about the preparation of shrimp and mice liver microsomal, detecting the liver microsomal protein content using BCA protein assay. The UDPGT metabolic enzyme activity was detected using the p-NP method. The protein content of liver microsomal in the shrimp is higher than the mice. The protein content ofliver microsomal in the shrimp and mice are 14.9 mg/g and 10.1 mg/g, respectively.Almost no UDPGT activity was detected in liver microsomal of the shrimp and the enzyme activity in mice is 24.23 pmol/min-1mg-1.The third chapter is the preparation of T-2 Glu A and exploring its optimal conditions using liver microsomal of shrimp and mice. None T-2-Glu A products was prepared using enzyme of liver microsomal in the shrimp owing to the different liver microsomal enzymes in the shrimp and mice. Using mice liver microsomal enzymatic synthesis of T-2-Glu A in vitro and exploring its optimal conditions, the results showed that with the increasing of the liver microsomal protein centration, the synthesis of T-2-Glu A increases correspondingly, the optimal incubation time is 90 min and the Triton X-100 concentration is 0.2%(w/v).On this basis, the fourth chapter we investigated the vitro metabolism of T-2 toxin in liver microsomal of the shrimp and mice, the metabolism of T-2 toxin in different animal liver microsomal metabolism exists obvious difference. The clearance rates for T-2 toxin of mice liver microsomal is 200 times that of the shrimp liver microsomal. This may illustrate that the damage to the shrimp is more serious as the remanence time of T-2 toxin in the shrimp is much longer. Due to the shrimp and mice have different metabolic pathways for T-2 toxin, the T-2 toxin metabolic products in the different liver microsomal are also different. The metabolic differences between aquatic animals and mammals also need further research. |
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